UPSC Prelims 2021 Answer Key | Science & Tech | UPSC 2021 Question Paper Solved | Paper Discussion

[@BharatKumar-vj5yy]

Question status moderate to difficult....no direct question. This time question was more deep explanation with basics. Some questions are pull from editorial concept. But very balance question. No Test series can make us profits.

[@Civilservicesaspirants77]

UPSC wants to select bookworm.

[@manphulbudania2198]

Here is my take on cooker question:- If I go by general meaning of pressure cooker it would mean a cooker that uses pressure to cook the food. So it boils down to what all affects the pressure 1) area of hole 2) temp of flame (higher the flame temp higher is heat transfer, higher the pressure) 3) weight of lid ( more weight=more pressure) So ans- D Let me know what u all think

[@durgeshchoudhary492]

lid and valve is different thing or same

[@kva9972]

My logic while attempting was exactly tge same. However no key that i looked so far claimed this as an answer

[@ronaldoningthoujam2495]

But the question is about the factors influencing the temperature. I think that's why weight of the lid should not be considered here. If it was asked like how fast the food can be cooked , then we can consider the pressure ( the weight of the lid ).

[@Ankitgupta-nv6dr]

I don't think weight of lid will have effect because modern cookers have very light weight lids than normal one.. Even if we go by electric cooker, then weight of lid doesn't play any role. Rest like every time, upsc will again escape controversy by not releasing answer key.

[@priyanshupandey5325]

The temperature of the pressure cooker will not depend on the intensity of the fire because each pressure cooker has a fixed boiling point ( Because lid is made keeping that in mind), if you give it more than that, it will come out as extra energy then it will depend only on lid and area so ans. 1 and 3 will correct according to myself

[@BharatKumar-vj5yy]

Boiling point is same.... But transfer of heat and energy maximum due high flame... This is also come to my mind. So Ans 123..

[@Baps978]

Bahoot harad…. Debatable…

[@bansimangla7077]

100% right bhai

[@ronaldoningthoujam2495]

No, you can't say the temperature of the pressure cooker doesn't Depend on the temperature of the flame. I get what you are saying , once it reached the boiling point, we cannot increase the temperature of the cooker any further but before reaching the boiling point it is the temperature of the flame that brought the temperature of the cooker from zero to boiling point.

[@Ankitgupta-nv6dr]

I have put my rice in pressure cooker and kept atop a candle flame. Dont know why its taking forever to cook.

[@UPSCWITHTAPASTEWARI]

Upsc lucent ko v nhi chhoda😱...Unpredictable public service commission

[@jitnapakkahe7395]

11th 12th physics, chemistry and biology yahi he sara question ka base.

[@mohdatif6651]

Ayse he lgra h lekin aysa hota nhi

[@kaushalgaur2131]

Mai 11th mai hu pcb se science base pr hi h

[@NishaKumari-zn9dh]

Thanks SIR now I'm in class12. I want to prepare of upsc with my 1st year graduation. But I'm very frightened from prelims specially in csat. So I watch your video in free time. It is very helpful 4 me . THANKS SIR 4 THIS🙏🏾🙏🏾🙏🏾🙏🏾

[@mayankchaudhary2578]

Sir end question ...speed of light is same only with one medium... When the medium is denser...the speed of light decrease...that also creates refractive index more....how it can be evaluated...because light travels in a straight line until there is any extra force...speed of light will be same in one medium... But when there is change in medium it differs... Also you can take black hole theory example

[@mahaswetadas805]

Sir optional ka kuch course he kya?..history

[@Drhinasheikh2707]

Virus ko artificial medium par culture nahi kar sakte. That doesn’t mean culture hi nahi kar sakte…. It just need a host, a living cell to multiply…. And that is y viruses are neighter living nor non living rather connecting link between them.

[@mr.perfect6540]

Mostly upsc becomes practical....u will get around 15 to 20 direct from practical where u need to apply ur logic to solve it rather it wont came by just studying books.....applications pe focus krna chahiye rather just doing everything from books by just rattafication or mug up.... Conceptual clarity must be there...then u will definitely able clear prelims

[@akhiltej4604]

Nice initiative

[@shubham-jt5th]

Sir prelium booster se koi bhi fasa yaa hamein source change krna pdega??

[@shubham-jt5th]

@@KS-su6fb no bro..there were some questions..like bisphenol and 3-4 more related to science which were in news..

[@shubham-jt5th]

@@KS-su6fb shayd is baar kuch nhi aya..pehle aata tha ..ab newspaper par hi rely krna pdega

[@AK-kj6yl]

On cooker questions I went with all And Othe science part is good as per the only IAS Answer key

[@teamtrader407]

Sir sources quote krne se kuch nhi hoga... 2018 me buland darwaja ka question sab ne proof diye the. It was not even doubtful question. Phir bhi ans. Neither 1 nor 2 tha

[@rashmipal2050]

Science padne ke liye kis class tk ki ncert pdni hogi

[@opjakhar648]

Jb aapko abhi tk confirm ni h fir ek student kaise solve kr skta h exam conditions m

[@swatantrayadav1438]

12th genetic chapter ncert bio....

[@AbhiKumar-gp9fe]

Sir my gs paper was good but I lacked in csat sir 😭😭

[@niharikamishra5475]

Sir virus ka culture bhi ho skta hai, corona bhi culture kiya gyaa thaa

[@SHILPEE____ART]

u can'nt sure.

[@harikapotupureddi2513]

Yes WE can culture a virus I am Ann MBBS student From culture only the microbiologist says which organism it is

[@niharikamishra5475]

@@harikapotupureddi2513 thanks

[@manik9583]

@@harikapotupureddi2513 r u sure about this???bcz every amswer key says it can't be cultured..

[@ashokyadav5632]

Biological weapons are artificially cultured.. Made in labs

[@Ankitgupta-nv6dr]

Sir i think led light can produce light 360, but its easier to engineer LEDs to produce focus light, which doesn't mean that it cannot be made to produce 360 if and equipment application demands

[@RamSingh-qx1hb]

kzbin.info/www/bejne/bWfSY42Bar2gbLc

[@indian8970]

Is bar sports se questions a gaya jo ajeeb tha...hamne to prepare hi nehi kiyatha

[@Baps978]

Both statements were wrong…. Those who follow cricket can easily relate…

[@vijaykumar-cp9hy]

Isi liye to unpredictable h, aur main epfo me isi wajah se bahar ho gya 185+ pr bhi. Jo prepare kiye usse km aa gya

[@DTUstudy251]

Bilkul yesa hi mere sath hua

[@PriyaPanchalInnosci]

Mera navratri ka vart hai...I watched abhi niyu vdo about significance of navratri vart, in that vdo he told we worship the mata becoz we get the dna mitochondria entirely from mother that is why mother or mata is worshipped..it's a coincidence that after watching the vdo I was sure about 2nd option...it means the question is asked from current affairs plus Indian mythology..I m glad to see this question..though m not an ias aspirant!

[@saloni5415]

It's mere coincidence UPSC just wants to be aware of all important facts everyday we should be a learner

[@Shipra21]

Dimaag kharab hai tera 😂

[@narendradhanwani5001]

Speed of light may be change as medium changes.

[@bishalkalita3388]

Science part was so easy.

[@abhishekkatruwar5743]

Sir in pressure cooker question ....temp of flame always remains same . Its the intensity of flame that matters.

[@letslearnmurtzaahmed7587]

think weight of cooker hoga... i.e material weight of cooker

[@DipeshTanwar]

11:36 question me led lamp k bare me poocha h , single led k bare me nahi poocha h .kzbin.info/www/bejne/a2Xai2euadhlrtk

[@opjakhar648]

Aaj nhi kr skte bt aaj se 10 sal baad to may be Pasible

[@Dark.eveything]

Sir speed of light also changes when medium change.there is solid reason for different refractive index in the space. I think light travel is the right answer.

[@tnverma_india]

It is said for simplicity that light slows down in medium but photons themselves never slows down really..its a different mechanism...search about it ...

[@opjakhar648]

Aaj ka ppr tough h jo pichle 2 sal se prep kr rha h

[@BANTIKUMAR-de6mk]

Sir telegram nahi open ho raha hai

[@Pragmatickk]

Sir g..plz..revise Q 38..deeply...

[@Bujho1]

sir wo three parent baby ka question hai na.. so only 2 correct

[@shreyajaiswal2374]

yup. last year bhi puchha tha...

[@Hanumanjikibhkt777]

Imp topic suggest karo pleas 🙏

[@parigupta3952]

pls sir iss pattern me prepare krne k liye source b share kijiye

[@rishabhdixit3189]

Hard ques 🙂

[@mryellow805]

Sir 36 wala aapka 100 percent galat hai iska keval b ya d none of these hoga kyonki mtritv prabhav me keval mitochondrial transfer hota hai aur first option me fertilisation k baad mitochondria transfer ki abhi tak koi technology nahi padhi hai sir ji

[@Naveendogra92]

light travel in straight line sir . so it shouldbe the answer

[@shahidbhat751]

Sir 38th question mein lid is part of body n is fixed. It cannot be the right option

[@nitishkrsingh5497]

Science ka questions ,,,UPPSC previous year se aaya hai

[@indian8970]

But sir India became the 1st country to culture virus in laboratory recently in news

[@educationhub7069]

Sir 1st Question ke 2nd option me virus bhi likha h virus me plasmid nhi hota to usme recombinant DNA technology use nhi hoti

[@wavee2496]

Definately ...so my answer was a

[@wavee2496]

Pr sari coaching institute c bta rahi h

[@souravkumarjha2876]

Same yaar plasmid ko use kiya jata hai as a vector na ki bacteria ya virus ko. But sab coaching C answer de rue hai

[@amanrajgupta5529]

8:39 D) hoga ! Reference : China 😂

[@surajsisodiya831]

Sci. and tech ke mostly que. logical guess se hi correct hue h.

[@shaludubey1701]

Bhyt hard paper tha aj ka sir

[@s.p.8548]

C can be correct answer

[@opjakhar648]

Or upsc aisa koi qsn ni puchti vo b s&t m jo aa possible h Or 10 sal baad n ho

[@chitrasingh7225]

Speed of light varies with medium that's called refraction

[@apurva8608]

I also applied the same logic and found that only b options' info is correct but unfortunately for mapping distance of stellar objects we dont get any other medium than vacuum

[@Ankitgupta-nv6dr]

Last time i went to school we called it bending of light. And Speed of sound varied with medium, not light. Gosh, Science has advanced much.

[@deveshagrawal5766]

it was very tough questions for me since i am not from SCI background! for me it was a setback!

[@ashutoshprasant1784]

Bhai tumse na ho payega.......

[@Yogeshsingh-dx1yk]

@@ashutoshprasant1784 chup reh

[@deveshagrawal5766]

@@ashutoshprasant1784 thanks for motivating!

[@saketgautam7226]

Sir velocity of light depend upon medium ..

[@ayushkumar-nb3xi]

Speed of light changes in different medium

[@ronaldoningthoujam2495]

Yes, but there is hardly or no medium at all when we talk about astronomical distances ,( eg, distance between planets, stars ,etc.). So lightyear is used only in this context.

[@sirsuspicious_official]

Thanks

[@vikassarin1685]

All flames have similar temperatures ranging from 175-210 celcius it depends on intensity of flame

[@prasadbhagwat5458]

Very easy question

[@vinayakmohanjha7746]

300 km per sec

[@Pragmatickk]

Speed of light km me glt hai..sir g...3 lakh km per second hota hai

[@Uthkarsh7575]

UPSC is gone made

[@Uthkarsh7575]

@@integrity2679 basically one who attempts less and gets most right with atleast 90 percent accuracy clears this exam even 60 qsns attempt with 7-8 mistakes would be good enough but can we do it is the question people want to attempt more but upsc pattern is changing

[@Uthkarsh7575]

@@integrity2679 s very true

[@saketgautam7226]

Upsc pattern is logic , inteligent guese not memorised stuff..

[@opjakhar648]

So plz 🙏

[@rupanshi7317]

Unidirectional h aur 360 degree m light produce kr rha h clear nhi hua...

[@OnlyIasnothingelse]

Omnidirectional…. not unidirectional.

[@asiffarhan5325]

Good evening sir

[@Neetmission-lv8gh]

Hello sir

[@swroopchand7897]

Water is not dipolar 🙄...it have polar bond

[@JJ-bw5sn]

Mere only 3 sahi hue 11 me se

[@opjakhar648]

Is baat ko smjho

[@vishwadeepupadhyay5458]

Tume naa aa rho tou hoo btay rhu 38 kou answer d hoyego

[@Travelshorts874]

Sir Synthetic virology is a branch of science where man made virus are produced

[@Eric..Cartman]

Virus are produced in labs. That's why China was blamed for manufacturing Coronavirus in Wuhan lab.

[@aman_870]

Respected sir, I filled test booklet code on OMR correctly but forgot to encircled the bubble on attendance code What will happen?

[@someloner7082]

That's not for us to fill. The supervisor will fill it up.

[@aman_870]

@@someloner7082 than you sir for your cordial response but I think I couldn't explain my doubt clearly to you. Actually I am talking about that separate attendance OMR( other than OmR in which we mark our answers) in which our test booklet code( A orB orC..) was asked along with its serial no.

[@opjakhar648]

Ye advanced technology h kuch b mr sakte h

[@Nishantsinghrajputparmar]

38 - (c)

[@vipulpareek9073]

Jitne questions Modern History m sahi hoye the utne hi galat Science and tech m hogaya....

[@opjakhar648]

Bt merit 88 se upr ni rahegi

[@indivaragnivesh5407]

300 km/sec! kya bol rahe hain.

[@ajayr7346]

There are LED lights which are 360 degrees 😅

[@sandeepnegi3106]

Yesss only 3 option is correct

[@wavee2496]

Mine too...

[@RahulRajputAhmedabad]

😔😊😔

[@opjakhar648]

Upsc ka only yhi targets h coaching ko khtm krna

[@Hello-by7kg]

Desh me berozgari itni hai coaching jaege sab govt job

[@अन्तिमपद]

kzbin.info/www/bejne/roDafYN3pMuljs0 upsc prelims answer key

[@khushijadaun9084]

Good evening sir